As Kargath observed, he's leaning forward out of the fire. Part of this is that it's a pyromancer, and is actually sending the fire. I mostly wanted to show that it controls it. That's why the fire brightens just as it happens, behind him.

Also, the idea of it shrugging off the fire like "oh wut you think I care about being on fire cause I DON'T" amuses me.

I muttered 'light as a board, stiff as a feather' for 2 days straight and now I've ascended, ;aughing at olympus and zeus is crying